0006195: Use compilerlibs instead of explicit lists of modules from the compiler

Description

Some tools which are part of the standard distribution (ocamldoc, ocamldebug, read_cmt, objinfo) embed some modules from the compiler. Instead of listing required modules explicitly, we could link against ocamlcommon.cma (and ocamlbytecomp.cma, if needed). This would simplify the Makefiles and make them more robust w.r.t. modifications of dependencies within compiler modules.

Note that ocamldoc modules are explicitly included (as opposed to linking odoc_info.cma + other modules). Point taken for the stdlib. This makes me wonder whether we should have a way to force including an entire library (i.e. -linkall restricted to a single library).